Wish I Kept My Copy of The Half-Assed Guide to Foundation Repair
August 20, 2020 8:33 AM Subscribe
An outside exposed corner of our 100+ years-old house's foundation is quite worn and crumbly. We've been working on it, but I would like advice for how best to proceed and products.
The corner is the most worn area, 4" deep in some spots, but damage radiates out in both directions for several feet. So far I and my father-in-law, who is not a mason but is very knowledgable in DIY, have been applying thin coats of bonding agent and portland cement and sand to the area. However, my FiL will now be unavailable for a while; his intention/parting advice was to drill holes for rebar, build a form for the corner and pour the rest. I'm reluctant to do this as the foundation was pretty crumbly even when we were driving small anchors for the small mesh to hold our initial thin coats, and my FiL, while a smart man, is also very impatient, so I've been looking up alternatives and have managed to get myself very confused.
So my questions are:
1) Would pouring into a form be the way to go, or just continue building up layers with bonder and cement/sand? I don't care if it's tedious or more work, I want to not have to worry about it when it's done. Also, if I should pour, how would I get it in the form? The cavity is shaped like a backwards C, so the form would be flush with the intact top of the foundation, no?
2) If pour is a go, should I use rebar? Would it make more sense/be less invasive to anchor a bent piece of 5x5/6x6 mesh in the corner?
3) Product advice: So far we've just been using portland cement. I live in a small city so material options are pretty much whatever the Home Depot has. I have sand, I have aggregate (Which we haven't used so far for our thin layers). Should I just buy another bag of portland cement and continue, or should I use something from Quikcrete's overwhelmingly vast family of confusing products?
4) I've seen a lot of mentions about the importance of air-entrained concrete for places with freeze-thaw cycles, but supplier websites don't tell me which products are entrained. Is it according to type?
5) There's a bit of a cavity in the overhanging part of the corner. Would it make sense to fill that cavity using a different product (Like some sort of quick-set or expoxy mix in an applicator gun) than just trying to cram concrete in there with a trowel?
Any further advice or experience you'd like to share would be much appreciated. Thanks!
The corner is the most worn area, 4" deep in some spots, but damage radiates out in both directions for several feet. So far I and my father-in-law, who is not a mason but is very knowledgable in DIY, have been applying thin coats of bonding agent and portland cement and sand to the area. However, my FiL will now be unavailable for a while; his intention/parting advice was to drill holes for rebar, build a form for the corner and pour the rest. I'm reluctant to do this as the foundation was pretty crumbly even when we were driving small anchors for the small mesh to hold our initial thin coats, and my FiL, while a smart man, is also very impatient, so I've been looking up alternatives and have managed to get myself very confused.
So my questions are:
1) Would pouring into a form be the way to go, or just continue building up layers with bonder and cement/sand? I don't care if it's tedious or more work, I want to not have to worry about it when it's done. Also, if I should pour, how would I get it in the form? The cavity is shaped like a backwards C, so the form would be flush with the intact top of the foundation, no?
2) If pour is a go, should I use rebar? Would it make more sense/be less invasive to anchor a bent piece of 5x5/6x6 mesh in the corner?
3) Product advice: So far we've just been using portland cement. I live in a small city so material options are pretty much whatever the Home Depot has. I have sand, I have aggregate (Which we haven't used so far for our thin layers). Should I just buy another bag of portland cement and continue, or should I use something from Quikcrete's overwhelmingly vast family of confusing products?
4) I've seen a lot of mentions about the importance of air-entrained concrete for places with freeze-thaw cycles, but supplier websites don't tell me which products are entrained. Is it according to type?
5) There's a bit of a cavity in the overhanging part of the corner. Would it make sense to fill that cavity using a different product (Like some sort of quick-set or expoxy mix in an applicator gun) than just trying to cram concrete in there with a trowel?
Any further advice or experience you'd like to share would be much appreciated. Thanks!
Foundations have two jobs: one is to look nice and square to the casual observer and not have gaping holes, the second is to hold the house up on a level platform to keep it from falling apart. I feel like you're fixing #1 and ignoring #2, which is the more important one. To make sure you also fix #2 I think you should get an expert to look at it. I think you might end up cutting out at least the whole corner, digging down, and pouring it in all one piece, after adding rebar into the parts that aren't crumbly.
If it's all crumbly, you can have the house lifted and a new foundation built under it. I had this done to my house, it's a big job but it saved the house.
posted by fritley at 9:19 AM on August 20, 2020 [2 favorites]
If it's all crumbly, you can have the house lifted and a new foundation built under it. I had this done to my house, it's a big job but it saved the house.
posted by fritley at 9:19 AM on August 20, 2020 [2 favorites]
Is the foundation your typical limestone rubble, with that ugly coating over the top? It was a "thing" in the 60s and 70s to cover brick or stone. Usually with a gypsum/mortar mix that...falls apart when it's done.
If so (is the foundation uncovered from the inside?) you need to knock all that shit off the stone and get the joints re-mortared. That's mason work.
posted by notsnot at 9:21 AM on August 20, 2020
If so (is the foundation uncovered from the inside?) you need to knock all that shit off the stone and get the joints re-mortared. That's mason work.
posted by notsnot at 9:21 AM on August 20, 2020
Seconding fritley. You need to think about the structural strength of your foundation, because if it fails, your house falls down (slowly). Your patching work has done nothing to rebuild structural strength. And probably, because it sealed in moisture, it assisted the continuing breakdown of the original foundation wall. Have a foundation pro check out the entire foundation, not just that corner.
posted by beagle at 9:47 AM on August 20, 2020 [2 favorites]
posted by beagle at 9:47 AM on August 20, 2020 [2 favorites]
Response by poster: Aw rats! When we first started we dug a shallow trench along the foundation to clear loose bits and see how far down the damage went and found it solid and intact, and so assumed the problem was largely cosmetic.
posted by Alvy Ampersand at 10:34 AM on August 20, 2020
posted by Alvy Ampersand at 10:34 AM on August 20, 2020
Depending on how long you have owned the house and how quickly this situation came about, I would also check with your insurance company to see if they might cover some of this. Most policies do not, but some will depending on what caused it and the circumstances around it.
I was able to negotiate some coverage for an issue that was not on the policy bc the next step, if it was not corrected would have been covered. We split the cost after my deductible. It was a roof issue, but it saved me a few thousand dollars off a new roof.
It is a long shot, but does not cost much to find out.
posted by AugustWest at 10:41 AM on August 20, 2020 [1 favorite]
I was able to negotiate some coverage for an issue that was not on the policy bc the next step, if it was not corrected would have been covered. We split the cost after my deductible. It was a roof issue, but it saved me a few thousand dollars off a new roof.
It is a long shot, but does not cost much to find out.
posted by AugustWest at 10:41 AM on August 20, 2020 [1 favorite]
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The only real fix here is to pull off all that whole crumbling top layer unil you reach solid material underneath, then reinstate the entire wall with something more weatherproof than what you've got now.
Talk to some builders & get some estimates.
posted by rd45 at 9:17 AM on August 20, 2020